Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It does add one useful constraint — '🆓 5 free trial calls per registered wallet' — which signals auth/trial economics. But it remains silent on output format, behavior when the trial is exhausted, rate limits, and what happens with missing or invalid inputs.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded: the purpose appears in the first clause, followed by the free-trial note. The only waste is the redundant 'x402-keywords:' prefix, which merely repeats the tool name.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with five semantically opaque parameters, no annotations, and no output schema, this description is not enough. An agent cannot determine which parameter receives the source text, what limit controls, what the response looks like, or how this tool differs from the similarly named x402-keyword-extract sibling. It covers the what but none of the how.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is nominally 100%, but every parameter description is a hollow template ('N to process', 'Term to process', 'Input to process') that carries zero semantic weight. The tool description implies 'text' is the object being processed, suggesting 'input' is the text, but it does not clarify what n, term, keyword, or limit mean, nor whether any are required. The description fails to compensate for the meaningless schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Extract keywords from text.' This is clear enough for an agent to understand the tool's core function. However, it does not differentiate from nearly identical siblings like x402-keyword-extract and x402-keyword-density, so it misses the top score.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus alternatives such as x402-keyword-extract, x402-keyword-density, or x402-word-frequency. The description does not indicate which parameter is the primary input, whether prerequisites like wallet registration are needed beyond the trial, or any selection criteria.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.